Dental cream containing benzalkonium halide and sulfa drug



Patented Apr. 7, 1953 DENTAL CREAM CONTAINING BENZAL- KONIUM HALIDE AND SULFA DRUG Joseph J. Kelly, Washington, D. 0., Charles F. Morgan, Falls Church, Va.,' and Edward Reed Smith, Washington, D. 0.; Catherine M. Kelly, administratrix of said Joseph J. Kelly, deceased No Drawing. Application July 28, 1949, Serial No. 107,384

3 Claims. (01. 167-515) This invention relates to dental therapeutic preparations and to methods of using the same, and more particularly to a non-toxic, non-irrating cream preparation for the preservation of the sterility of exposed dental pulp.

While it is known that abnormal exfoliation time of both deciduous and permanent teeth is hastened by bacterial invasion of exposed dental pulp due to necrosis of the same, up to the present time only complicated and difiicult means have been utilized for successfully arresting the progress of the invasion, and ultimate death of the pulp; The result has been that many teeth have been lost prematurely where the availability of simple treatment capable of being carried out in a dental ofiice with standard equipment might have avoided expensive orthodontic treatment or artificial restorations as well as other pathological conditions whose etiology is premature loss of deciduous teeth.

The main object of the present invention is to provide a therapeutic preparation capable of easy application to exposed dental pulp for the prevention of premature loss of deciduous teeth, or for the restoration to normal function of vital permanent teeth having exposed pulps.

Another object is to provide a preparation which is non-toxic and non-irritating in character, and capable of exercising a detergent as well as a germicidal action.

Another object of the invention is to provide a: preparation capable of destroying bacteria in exposed dental pulp and exerting a continuing germicidal action for this purpose thereby allowing the pulp to heal and permitting the insertion of a permanent restoration.

A further object is to provide an agent capable of maintaining sterility of exposed dental pulp and-simultaneously exerting a mild stimulating action such as to encourage the formation of secondary dentin.

-A still further object is to prevent disfiguration of. the permanent dental arch by early loss of deciduous and permanent teeth resulting from traumatically or pathologically exposed pulps.

Numerous other advantages and objects of the invention will appear from the following specification.

By way of introduction, it may be pointed out that human teeth are composed, of the core or dental pulp containing nerves and blood vessels, the dentin which encloses and protects the pulp, and the exterior enamel. Exposure of the pulp results in bacterial invasion followed by rapid necrosis of tooth structure, particularly deciduous or first teeth, the premature loss of which exerts an important effect upon the formation of the second or permanent teeth and of the dental arch. Premature loss of the deciduous molars results in drifting of the adjacent teeth and produces malformation of the dental arch capable of correction only by long and costly orthodontic treatment. The same condition is also met in the case of permanent teeth, and more particularly the six-year molars, which most often present this condition.

We have found that a relatively simple treatment of exposed dental pulp may stop its necrosis and, in some instances, actually encourage the formation of secondary dentin over the pulp area which has been exposed. i

The invention is concerned with a preparation to be applied to the exposed pulp to sterilize the parts affected, and to exercise a detergent and antiseptic action capable of prolonging th life of the tooth. a

Extensive clinical studies have demonstrated the eihcacy, for accomplishing the above objects, of a preparation composed of a mixture of a sulfa drug, a germicidal detergent capable of synergistic action which the sulfa drug, rendering it more soluble, and a bland unguent base or carrier of a particular type.

The sulfa drug functions as a germicidal bacteriostatic agent to destroy the organisms which causes necrosis. Its action is multipled by the synergistic action of at least one of the ingredients with which it is used.

The term sulfa drug as used herein is intended to embrace not only the common sulfa drugs such as sulfanilamide, sulfathiazole, sulfapyridine, sulfadiazine and sulfamethylthiazol, but also their derivatives.

The germicidal detergent used is a member of the class of quaternary ammonium compounds having a low tissue toxicity and a phenol coefficient above unit. It acts in conjunction with the sulfa constituent to greatly amplify the germ-killing action of the preparation'while exhibiting a low surface tension permitting close and effective contact with mucous membrane. One member of this class of compounds which exhibits the desired characteristics is a compound known as Zephiran chloride and. having the chemical name of alkyl dimethyl benzyl ammonium chloride. Important characteristics of this material are its germicidal stability and potency, its ability to affect bacterial organisms and fungi both antiseptically and germicidally, and its synergistic action with sulfa drugs. While the effectiveness of different materials of this class may vary, the properties of Zephiran chloride" are typical, its tissure toxicity'i's low being only 0.48 whereas that of phenol is 4.0. Its phenol coefiilcient is, on the'other hand, 5'79 as compared with the value of 1.0 for "the phenol. Thus it exhibits-to a marked degree the characteristics which we havefound to he most desirable for the treatmentnf dental'pulp according to the present invention.

By low tissue toxicity is meant toxicity .low enough not to irritate delicate dental tissues which are among the most delicate in the body.

Zephiran chloride is soluble in acetone and alcohol, but it is also i-freely soluble in water .fomning a. clear, colorless,-almost odorless .solu- .tion. Because of its effective action itzispreferably iisedin highly diluted form, :e. g., one part of Zephiran: chloride with one thousand parts of water having been found to behighly satisiafactoryfor thepurposesof the present invention.

The dilutionis, however, subject to some varia- ;tion.

The third anda'necessary ingredient'of the preparation is a bland unguent base or carrier nnd'comprising anemulsion of the water-in-oil type. An example .of a carrier of this type is sa preparation known as .aquaphor and described ;by its makers as an inert grease base .of vEucerite (alcohols and esters of the cholesterol groups with solid and liquidhydrocarbons) This material is efiective, and ispreferred, because of'its compatibility with the quaternary ammonium .compoundssespecially when-in contact with mucous membrane. .It'may also actas an emollient to allay irritation.

Other unguent carriers which might be used are water-in-oil emulsionsof lanolin,.lard, pet- ;rolatumandthelike, but in any event it is. essential that the emulsion -haveia surface tension such as to produce a wetting action .on moist mucous membrane.

.The .preparationais compoundedinknownmannerby combining .from about to 7 5% of the sulfadrugwith from 15 to 125% of the Zephiran chloride. in 1:1000 dilution, 'and'then'dispersing it in the carrier to makeup :a total of 100% by weight. The result is an unguent paste of low surface. tension, capable of close adherence to mucous membrane and characterized by itslow toxicity and by its ability toremain effective over substantial periods of time when .in contact with dental pulp.

The percentages of ingredients are not extremely.criticalprovided the toxicity is kept low, buteit is essential that the preparation .be stiff enough for ready application with a dental spoon but plastic enough to maintain-close contact with the exposed areas to-be treated.

The general method of application consists in removing the decayed portionof the tooth to be treated using a burr and hand instruments until the :exposedpulp is cleared of debris. Thecavity area should then be wiped and sterilized :in the usual manner using :somematerial compatible with the cream and in any event a non-caustic material of low tissue toxicity. The sulfa preparation is then gently wiped over the exposed area to substantially cover the same. This may be characterized as a sulfa cap. A mixture of zinc oxide and eugenol or equivalent material is then placed over the sulfa cap for protective purposes, and a coating of zinc oxyphosphate cement or its equivalent applied. The tooth may then be given a ten-day rest period beforeplacing-the amalgam,

orthe amalgam may beplaced at once with care to prevent too great a pressure shock to the pulp. The treatment after placing the preparation may conform to standard practice.

Thesulfa'cream remains in contact with the pulp and exerts a continuing germicidal, bacteriostatic efiectlresulting in a sterilizing action so-thatno further decay occurs and the tooth .may continuedtsznormal life as if no pulp had been exposed. Among three hundred and thirtyfour clinical cases treated as indicated above,

'threehundred and twenty-three were successful,

and no toxic effects on the patients were observed even though certain of the patients were known to be sensitive to sulfa drugs. In at least one case, a toothtreated as :aboveshowed, after a capped. period of one year,- that :aheavy section of .dentinhad formed over the exposed. pulp and under the capping material. .Ineverycasethe treatment with proper cooperation on 'thepart of the patient resultedin complete cessation of further pulpal involvement and such continued vitality of the teeth as might havebeen expected in'a vita-lfilled tooth having no. pulp exposure.

It is evident from' theabove and that we have produced a combination of ingredients that are more efiective under these conditions where no efiective results have ever before been achieved. It is well to note that the cases selected were routineand as found in a-general dentalv practice. The synergistic action of the quaternary ammonium compound and the sulfa drug, when aided by the unguent base, results in an unexpected and outstanding resultlong desired but never beforeachieved. It is, therefore, to be understood that while only a fewexamples from each class of ingredients have been named,-these are exemplary only and theinvention isto be construed as covering such equivalents as will be evident to those skilled in the art-after reading the abovespecification.

Having thus described the invention, we claim:

1. A non-toxic non-irritating therapeutic cream for the treatment of exposed dental pulp comprising from about .'5% to about 7 5% of a sulfa drug, from about .015% to about .025%.of benzalkonium halide having low tissue toxicity and a phenol coefiicient in excess of unity, said compound being capable of synergistic action with the sulfa drug, and a bland unguent carrier of the water-in-oil type .for binding the sulfa drug and the ammonium compound together, and causing continuing germicidal and bacteriostatic action on the pulp towhich-the cream is applied.

2. A non-toxic non-irritating therapeutic cream for the treatment ofexposed dental pulp, comprisin-g'from about one-half toabout 75% of sulfanilamide, approximately ;0l5% to .025% of alkyl dimethyl-benzyl ammonium chloride, and the remainder a bland unguent carrier emulsion of the water-in-oil type.

3. The method of treating exposed dentalepulp to arrest decay therein which comprises applying to said exposed pulpa mixture ofaiblandunguent carrier in the form of a water-in-oil emulsion, froin ebout .5% to about 75% of a. sulfa drug, and from about 0.15% to about .025% of a benzalkonium' halide having low tissue toxicity and a phenol'coeflicient in excess of unity, and then sealing 'said mixture in contact with said pulp.

JOSEPH J. KELLY. CHARLES F. MORGAN. EDWARD REED SMITH.

me of this patent:

6 UNITED STATES PATENTS Number Name Date 2,429,404 7 Dixon Oct. 21, 1947 OTHER REFERENCES- Eigen, J. American Dental Association, July 1, 1944, pages 902 to 909.

Gershenfeld, Am. J. Pharm., July 1946, pages 228 to 229, 235.

Prinz, Dental Formulary, Lea, and Febiger, New York, 1923, pages 215 to 219.

Huyck et aL, J. A. P. A., Scientific Edition, May 1946, volume XXXV, Number 5, pages 129 to 139. 

1. A NON-TOXIC NON-IRRITATING THERAPEUTIC CREAM FOR THE TREATMENT OF EXPOSED DENTAL PULP COMPRISING FROM ABOUT .5% TO ABOUT 75% OF A SULFA DRUG, FROM ABOUT .015% TO ABOUT .025% OF BENZALKONIUM HALIDE HAVING LOW TISSUE TOXICITY AND A PHENOL COEFFICIENT IN EXCESS OF UNITY, SAID COMPOUND BEING CAPABLE OF SYNERGISTIC ACTION WITH THE SULFA DRUG, AND A BLADE UNGUENT CARRIER OF THE WATER-IN-OIL TYPE FOR BINDING THE SULFA DRUG AND THE AMMONIUM COMPOUND TOGETHER, AND CAUSING CONTINUING GERMICIDAL AND BACTERIOSTATIC ACTION ON THE PULP TO WHICH THE CREAM IS APPLIED. 